This invention relates to a balancer device for internal combustion engines and more particularly to a balancer arrangement for V-type engines wherein the angle of the V is other than 90.degree..
As is well known, reciprocating internal combustion engines give rise to numerous unbalanced forces that can cause vibration. The reciprocation of the piston within the cylinder generates a first order inertial force in accordance with the reciprocating movement of the piston. This inertial force is exerted upon the crankshaft and can cause vibrations unless balanced. When an engine is configured with two cylinders having the pistons reciprocating at right angles to each other (90.degree. V), some of the first order forces are balanced and engine vibrations reduced. On the other hand, in some instances, it is necessary or desirable to provide a V-type engine in which the cylinders are not disposed at right angles to each other. When this is done, the first order forces can be magnified rather than reduced.
In addition to the first order inertial forces in V-type engines, it is a common practice to offset one cylinder and connecting rod from that of the adjacent bank. This is frequently done so that the connecting rods can cooperate with a single throw of the crank. When offset connecting rods are employed, a force couple is also exerted on the crankshaft from the first order forces transmitted to it by the connecting rods. Of course, such force couples also can give rise to vibrations and shakes if not appropriately balanced.
It is well known to employ counterweights on the crankshaft throws so as to balance the first order inertial forces generated by the reciprocation of the pistons. In many instances, it is difficult or impossible to provide sufficient counterweighting directly on the crankshaft so as to dampen all first order forces. This problem is particularly acute when the engine is extremely compact, as is always desirable.
In addition to the provision of counterweighting for balancing first order forces, the force couple is normally balanced by two separate balancing devices. Thus, with engines of the V-type wherein the angle is other than 90.degree., the balancing system using prior art devices becomes extremely complicated and cumbersome.
It is, therefore, a principal object of this invention to provide an improved and simplified balancing arrangement for an internal combustion engine.
It is a further object of the invention to provide an engine balancing arrangement for a V-type engine wherein the angle between the cylinders is other than 90.degree..
It is a still further object of this invention to provide a compact, highly effective balancing system for a V-type engine that eliminates both first order and couple forces.